BICYCLO [3.2.1 IOCT-3-EN-2-OLS
March 20, 1961
and dried solution there was obtained 210 mg. (79%) of a solid, m.p. 154-155', which had m.p. 155-156' when recrystallized from 95% ethanol. This product was identical with an authentic specimen of diphenylmaleic anhydride, prepared from phenylacetonitrile." Identity was established by comparison of infrared spectra and by m.p. of the mixture of substances. Dehydrochlorination of a,a'-Diphenylsuccinyl Chloride .To a deoxygenated solution of 6 g. (1.76 mmoles) of diphenylsuccinyl chloride in 130 ml. of dry benzene, there was quickly added, under a nitrogen atmosphere, 7.91 g. (7.82 mmoles) of triethylamine. The mixture rapidly colored and was brilliant crimson in 1 hour. The infrared spectra of samples of the supernatant benzene solution taken after 3 and 20 hr. were identical and shomved no band a t 4.8 P but maxima a t 5.72, 5.85 and 6 . 1 8 ~ . The reaction mixture was filtered and the benzene solution filtrate washed SUC(38) C. L. Reimer, Bcr., 131, 742 (1880).
[CONTRIBUTION FROM
THE
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cessively with three 50-1111. portions of 1.2 N hydrochloric acid, three 100-ml. portions of water, 10% sodium carbonate solution, water and finally dried. Evaporation of the benzene solution left a gummy oil residue from which, after extraction with 95% ethanol, 100 mg. of a bright yellow solid was obtained, m.p. >360°. After three recrystallizations from chloroform this solid 5.65 p . had m.p. 394-396' and::A:
Anal. Found for solid of m.p. 39-1-396': C, 80.79; €1, 4.21; mol. wt., 531 (isothermal dist. from CHC18). From the ethanol extract mentioned above several fractions, ca. 1.1 g. total weight, of m.p.'s less than 100' were obtained. None was exanlined further. Another yellow solid product, ca. 0.5 g. and of m.p. below loo', mas isolated hy aqueous washing of the precipitated triethylamine hydrochloride and in part by gradual precipitation from the acid wash of the original benzene solution.
DEPARTMENT OF CHEMISTRY, THEUNIVERSITY OF WISCONSIN, MADISON 6, WIS.]
Ionic Reactions in Bicyclic Systems. E. The Preparation and Assignment of Configuration of the Isomeric Bicyclo [3.2.1 Ioct-3-en-2-01s and Bicyclo [3.2.1 loctan-2-01s BY HARLAN L. GOERING,RICHARDW. GREINER~" AND MARTINF. S L O A N ~ ~ RECEIVED SEPTEMBER 24, 1960 Deamination of e~zdo-5-arnit1obicyclo[2.2.2]oct-2-ene (I) and acetolysis of fndo-bicyclo[2 2.21oct-5-en-2-yl p-tolucncsulfonate (IV) give derivatives of cxo-(axiul)-bicyclo[,1.2.l]oct-3-en-2-o1 (IIa). Endo-(eiluntoriaZ)-Bic)iclo[,1.211oct-3-en-2-01 (IIb) and the isomeric bicyclo[3.2.l]octan-2-ols (VI) have been prepared and their configurations established.
This paper describes the synthesis, properties and configurational assignments of the isomeric bicyclo I3.2.1]oct-3-en-2-ols (11) and the isomeric bicyclo [3.2.1]octan-2-ols (VI). These compounds were of interest in a study of carbonium ion (solvolytic) reactions in [2.2.2]-and [3.2.l]bicyclicsyst ems. Several years ago the conversion of endo-5-aminobicyclo[2.2.2]oct-2-ene (I) to bicyclo[3.2.l]oct-3en-2-01 (11) by nitrous acid deamination was reported by Wildman and Saunders2 The structure of the deamination product was determined by oxidation to bicyclo [3.2.1Ioct-3-en-2-one (111) and reduction to a bicyclo[3.2.l]octan-2-01 (VI).2 However, the configuration of the product was not established. I n the present work it was found that I1 produced by deamination of I has the exo or axial configuration (IIa). Solvolysis of the endo-ptoluenesulfonate (IV) also gives derivatives of exo-(axiul)-bicyclo[3.2.l]oct-3-en-2-ol (IIa). Because of the availability of endo-bicyclo [2.2.2]oct5-en-2-01 (V) and thus of the corresponding p-toluenesulfonate IV the latter transformation represents a convenient stereoselective synthesis of IIa. As indicated by the structural illustrations, IIa can be converted to its epimer I I b by oxidation to the ketone I11 and subsequent reduction of the carbonyl group. The unsaturated [3.2.1]bicyclic alcohols I1 can be converted to their saturated analogs 1'1 by reduction of the double bond. The Synthesis of the Isomeric Bicyclo 13.2.1 1oct-3-en-2-01s (11).-endo-5-Aminobicyclo [2.2.2]oct-2-ene (I) was prepared from endo-5-carboxybi(1) ( a ) Socony-Mohil Co. Fellow, 1950-1957. (h) Wisconsin Alumni Research Foundation Fellow 1956-1958: National Science Foundation Fellow 1958-1960. (2) W. C. Wildman a n d D. R. Saunders, J . Ani. Chcm. Soc., 76, 940 (1954).
cyclo [2.2.2]oct-2-ene hydrazide by the Curtius reaction. The latter was prepared from ethyl endo-bicyclo [2.2.2]oct-2-en-5-carboxylate obtained from the reaction of cyclohexadiene with ethyl a~rylate.~ A similar synthesis of I has been reported recently.4 The endo-amine I was converted to exo-(axial)bicyclo[3.2.1Ioct-3-en-2-01 (IIa) in two ways: aqueous nitrous acid deamination2 and nitrous acid deamination in acetic acid followed by saponification of the resulting acetate. The products obtained by the two routes were indistinguishable. Physical properties of the deamination product IIa (including the infrared spectrum) were unchanged by chromatograpliy (Florisil) or recrystallization of the p-nitrobenzoate derivative to a constant melting point. However, as will be shown later, there is evidence that this product is not completely homogeneous. The axial [3.2.l]bicyclic alcohol IIa was also prepared from endo-bicyclo (2.2.21oct-5-en-2-yl p-toluenesulfonate (117) which in turn was prepared from the corresponding alcohol V. The latter was obtained from its acetate which was prepared from cyclohexadiene and vinyl acetates6 The endo-ptoluenesulfonate IV derived from V was contaminated with about 10% of a more reactive isomer which was removed readily by recrystallization from ethanol. endo-Bicyclo [2.2.2]oct-5-en-2-01(V) purified by recrystallization of its p-nitrobenzoate derivative apparently was homogeneous and gave pure p-toluenesulfonate IV (identical with material from which the reactive isomer had been removed). The infrared spectrum of a 0.1 AI solution of the (3) R S r k a and 0. Tramposch, Bcr., 75, 1379 (1942). (4) C. A. Grob, K. K n y and A. Gagnebx, Helo. Chrm. Acto, 40, 130
(1957). (6)
K,Alder
and H. Rickert, Ann,, 64S, 1 (1940).
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HARLAX L. GOERING, RICHARD W. GREINERA~YDLIARTIN F. SLOAN
pure endo-alcohol V in carbon disulfide contained three bands in the hydroxyl region: 3617 f 2 (non-hydrogen bonded hydroxyl), 3593 i 1 (intramolecular hydrogen bond with double bond)6 and 3490 i 50 cm. -l (intermolecular hydrogen bond) .7 Tenfold dilution of the solution did not affect the extinction coefficient of the 3593 ern.-' band but resulted in the disappearance of the 3490 50 cm.-l band. The presence of an intramolecular hydrogen bond, which must involve the hydroxyl group and the double bond,6 establishes the configuration of the alcohol V and thus of the corresponding p-toluenesulfonate IV. Acetolysis of pure endo-bicyclo [2.2.3]oct-5-en-2yl p-toluenesulfonate (IV) for ten half-lives (the kinetic results will be presented in another paper6) followed by saponification of the resulting acetate gave I I a in good yield. The product obtained in this way was slightly different from that obtained by deamination of I. For example, IIa derived from the tosylate melted 10 degrees lower than the deamination product. Moreover the p-nitrobenzoate melted about 7 degrees higher than that of the deamination product. The infrared spectra of the two p-nitrobenzoates were indistinguishable. However, the spectra of the alcohols were slightly different. That of the deamination product had several very weak bands which were absent in the spectrum of the alcohol derived from the pure p toluenesulf onate It appears that the exo-(axial)-alcohol IIa prepared from pure p-toluenesulfonate IV is homogeneous. Gas chromatography gave a single sharp peak and the physical properties (including the infrared spectrum) were not changed by conversion to the p-nitrobenzoate derivative followed by saponification after several recrystallizations. The spectrum showed that this product was not contaminated with its epimer IIb. Hydrogenation of I I a prepared in this way gave pure exo- (axial)-bicyclo[3.2.l]octan-2-01 (VIa). The nature of the impurity in I I a prepared by deamination of I remains obscure. The complete absence in the infrared spectrum of bands characteristic of endo-bicyclo[2.2.2]0ct-5-en-2-01 (V) or endo-(equatorial)-bicyclo [3.2.1Ioct-3-en-2-01 (IIb) indicated these compounds were not present. It is perhaps significant in this connection that I I a prepared by solvolysis of p-toluenesulfonate IV from which the reactive contaminant had not been removed was essentially the same as that prepared by deamination. This suggests that the impurity in Ha, derived from impure p-toluenesulfonate IV and endo-amine I, results from the presence of exo isomer in the reactant. In other words, according to this idea, the two Diel~-~4lder reactions (preparation of I and V) give adducts containing the ex0 isomer which is not removed by the usual purification procedures. Presumably endo-amine I and endo-ptoluenesulfonate I V give pure IIa, and exo-amine and exo-p-toluenesulfonate give products isomeric with I I a which are extremely difficult to separate
*
I
(6) P. v. R. Schleyer, U S. Trifan and R. Bacskai, J . A m C h e m .Sf>
